1. Field of the Invention
The present invention relates to mobile timber cutting and handling apparatus of the type using blades for shearing trees and grapple arms for clamping trees so that they can be moved in upright position to a piling or yarding area.
2. Prior Art
Horncastle U.S. Pat. No. 3,102,562 discloses "Tree Felling and Bunching Mechanism" including "gripping means for gripping an upright tree at its base" (column 1, line 47) and "sawing means for sawing through the trunk of a tree below the gripping means" (column 1, lines 49 to 50), each of such means being carried by a boom pivotally mounted on a tractor. In use, the tree-gripping mechanism is maneuvered to grip a standing tree, the tree is severed by the sawing mechanism and the gripping and sawing mechanism are tilted to lower the tree.
Earl U.S. Pat. No. 3,074,446 discloses a "Machine for Harvesting Trees" including an upright U-shaped "tree receiving jaw", "roller grippers" movable through apertures in the jaw to grip a tree and a chain saw swingably mounted at the lower end of the jaw. Support structure pivotally mounts the jaw on the side of a crawler tractor. In use, a standing tree is received in the jaw and gripped by the roller grippers, whereupon the chain saw is swung to sever the tree. The tree is swung downward and delimbed as the roller grippers move it lengthwise of the jaw.
In the "Apparatus for Harvesting Trees" of Larson et al. U.S. Pat. No. 3,238,981, tree-delimbing mechanism is movable vertically along an upright rail. Tree-severing mechanism, such as a chain saw, is swingably mounted at the bottom of the rail. The rail is mounted on a boom carried by a tractor.
Also known is the "Model TS-15 Feller-Buncher" manufactured by Allen Hydraulics Co. As shown in the operating manual, such feller-buncher includes grapple arms for clamping an upright tree and swingable jaws including shear blades for severing a tree, the grapple arms and jaws being swingably mounted on a tractor.